The present invention relates to a camera capable of making communication with an external device via interface of various standards.
Various techniques for allowing a camera and a personal computer to make mutual communication via the serial interface have been developed.
For example, Jpn. Pat. Appln. KOKAI Publication No. 10-75390 and Jpn. Pat. Appln. KOKAI Publication No. 10-136245 disclose the technique relating to a camera system which allows a camera and a personal computer to make communication via the serial interface of the standards such as RS232, USB, IEEE1394 or the like to exchange the image data.
In this communication, the camera has made various kinds of communication operations by a power supply such as a lithium battery, an alkaline battery and the like provided in the camera body, or by a domestic power supply fed via a DC adapter.
However, when the communication operations are made by the power supply of, for example, a lithium battery or an alkali battery, provided in the camera body, inconvenience that the battery capacity becomes short during the communication operations and interrupts the operations has occurred. In this case, the communication could not be made again without exchanging the battery.
Further, in a digital camera, for example, large power is consumed. Therefore, it is connected to the domestic power supply via a DC adapter when the communication operations and the like are made. However, when the communication operations are made by the domestic power fed via the DC adapter, connection of the DC adapter needs to be made besides the connection of the serial interface, which requires complicated works.
On the other hand, today, the USB, IEEE1394 and the like of the serial interface standards have a power supply terminal (for example, a 5-V power supply in the USB) and a GND terminal, and users have expected use of these terminals. In the above prior art, however, feeding the power from a personal computer via the serial interface has not been suggested at all.
A CCD camera which always receives the power from the only personal computer has been already developed. However, it has not accompanied a power supply operated independently thereof, and therefore, the use of the camera has been limited.
The present invention is accomplished by considering the above-described problems, and its object is to provide a camera which can prevent interruption of the communication operations caused by shortage of battery capacity, during the communication between the camera and an external device such as a personal computer or the like, and which does not require an external power supply during the communication.
To achieve the object, there is provided, as the first embodiment of the present invention, a camera having a power supply and an electric circuit operated by the power supply, and comprising: a connector section which comprises a terminal for communication with the personal computer and a power supply terminal for receiving power from a power supply in the personal computer, and which makes connection with a personal computer; a detection circuit for detecting that the personal computer is electrically connected to the connector section; and a power supply control circuit for controlling to supply the power from the power supply in the personal computer, instead of the power supply in the camera, to the electric circuit when the detection circuit detects the connection of the personal computer.
As for the second embodiment, there is provided a camera comprising: a power supply; a plurality of camera operation means for executing a predetermined camera operation; connector means for making connection to a personal computer; detection means for detecting that the personal computer is electrically connected to the connector means; and power supply control means for controlling to selectively supply power from any one of the power supply in the camera and the power supply of the personal computer to the camera operation means. The connector means comprises a power supply terminal for receiving power from a power supply in the personal computer. The power supply control means selects the built-in power supply when the personal computer is not connected to the connector means and selects the power supply in the personal computer when the connection of the personal computer is detected by the detection means.
As for the third embodiment, there is provided a camera having a power supply and a circuit operated by the power supply, and comprises: connector means which comprises a terminal for communication with the computer and a power supply terminal for receiving power from a power supply in the computer, and which makes electric connection to a computer, and power supply control means which controls to supply power from the power supply in the computer instead of the power supply in the camera to the circuit when the computer is connected.
As for the fourth embodiment, there is provided a camera comprising: a camera operation mechanism for executing a predetermined camera operation; a power supply; a connector section which comprises a power supply terminal for receiving power from a power supply in the external device, and which makes electric connection to an external device; a detection circuit for detecting that the external device is connected to the connector section; and a power supply control circuit for selecting any one of the power supply in the camera and the power supply in the external device, as a power supply for the camera operation mechanism, in accordance with a result of the detection of the detection circuit.
As for the fifth embodiment, there is provided a camera comprising: a plurality of electric circuits for executing a predetermined camera operation; a power supply which is built in the camera; a connection terminal for making connection to external devices including a power supply; and a power supply control circuit for selecting any one of the power supply in the camera, and the external device power supply connected via the connection terminal, as a power supply for the plurality of electric circuits.
AS for the sixth embodiment, there is provided a camera system having a camera and an external device which can be connected to the camera. The external device comprises: an external device side communication terminal for making electric connection with the camera; and a power supply circuit. The camera comprises: a camera side connection terminal for making electric connection with the external device; a plurality of electric circuits for executing a predetermined camera operation; a power supply which is built in the camera; and a power supply control circuit for selecting any one of the power supply in the camera, and the external device power supply connected via the connection terminal, as a power supply for the plurality of electric circuits.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.